Thieme Mumenthaler, Neurology - part 8 potx

sys-Information from the vestibular, sual, and proprioceptive systems con-verges in the central nervous system,where it is integrated and determinesthe motor response that regulates vi-6

Table 9.14 Differentiation of peripheral and central vestibular disturbances

Nystagmus Rapid component to the left May be vertical, rotatory, or

dissociated (i.e., only able in one eye in particularpositions); may be accompa-nied by other brainstemsigns

detect-Excitability of

Other > Romberg test: fall to right

> Walking a straight line:

deviation to right

> Unterberger stepping test:

more than 45% turn toright after 40 steps

> Arm position test:

“dysharmonie vestibulaire”)

tion (cf positional nystagmus,

p 695) The various types of

nystag-mus and their localizing significance

are described on p 643

The features that distinguish central

from peripheral vestibular disorders

are important to know and are

sum-marized in Table 9.14.

Various tests of stance and gait are

useful in the demonstration of

vestib-ular disturbances (and other types of

disturbances causing

dysequilib-rium), particularly the Unterberger

step test and the Babinski-Weil

walk-ing test In the B ´ar ´any pointwalk-ing test

(see Fig 9.31), the patient extends his

arms and points with his index

fin-gers to the examiner’s index finfin-gers

He is then asked to close his eyes and

advance his index fingers straight

for-ward to touch the examiner’s fingers

In the presence of a vestibular lesion,

the patient’s fingers deviate to theside of the lesion

The brain has multiple sources of formation that help it to maintain thebody’s balance and orientation in

in-space (Figs 9.27, 9.28): the vestibular

apparatus, the visual system, and theproprioceptive system (in which im-pulses from the peripheral nerves arerelayed to the spinal cord and upward

to the cerebellum If one of these tems should cease to function, thebody can remain in balance, but iftwo or all three cease to function, dy-sequilibrium arises Patients experi-ence this as unsteady gait, subjectiveimbalance, and vertigo

sys-Information from the vestibular, sual, and proprioceptive systems con-verges in the central nervous system,where it is integrated and determinesthe motor response that regulates

vi-692 9 Diseases Affecting the Cranial Nerves

Visual system, eye movements

Fig 9.28 Maintenance

of balance by tion of information from multiple channels.

integra-muscle tone and body posture A

ma-jor role is played by reciprocal

connec-tions between the visual and

vestibu-lar systems and by motor control of

the eyes and head, which depends on

the normal functioning of the

cerebel-lum and cerebral cortex (see also

ocu-lar motility, p 634) If all of the

infor-mation converging on the CNS is

con-sistent with prior experience, it is

pro-cessed without reaching the level of

consciousness, and the individual

re-mains unaware of it If, however,

infor-mation arrives that is inconsistent

with prior experience, an unpleasant

sensation generally arises, namely,

vertigo (This is an outline of the

so-called mismatch hypothesis.) If this

sensation persists, the individual feels

unwell and begins to suffer from other

vegetative phenomena such as nausea,

diaphoresis, salivation, or vomiting

Physiologic vertigo Individual

expe-rience has trained the brain of each of

us to expect a certain amount of shift

in the retinal image of the

environ-ment when we take a step forward If

we stand on top of a mountain or scraper, the retinal image of the nowvery distant objects around us shiftsmuch less than we are accustomed towhen we move As a result, we be-

sky-come nervous or dizzy (height ness, acrophobia) This is one example

dizzi-of normal, physiologic vertigo;

an-other is motion sickness, with its ants carsickness and seasickness, in

vari-which unusual movement of thebody creates a conflict between vi-sual and vestibular input, and therebyproduces vertigo

Pathological vertigo Temporary or

persistent, functional or structuralimpairment of the vestibular, visual,

or proprioceptive systems or of thecentral integrative mechanism alsocauses “mismatch” and, therefore,pathological vertigo The diagnosticevaluation of vertigo has two pur-poses: localizing its site of origin anddetermining its etiology

Disturbances of the Vestibulocochlear Nerve 693

Clinical History

The patient’s spontaneous

descrip-tion of vertigo is rarely precise

enough to yield useful information

for diagnosis Thus, the clinician must

know what specific questions to ask

to bring the diagnostic process

fur-ther The most important points to be

clarified are listed in Table 9.15.

Historical Clues to Differential

Diagnosis

The subjective quality of vertigo may

already constitute strong evidence for

or against a vestibular disturbance

Directional sensations such as

rota-tion, a “carousel” feeling,

lateropul-sion, or a feeling of being lifted are

more likely to be due to a vestibular

lesion than such sensations as

reel-ing, staggerreel-ing, dazedness,

quasi-drunkenness, lightheadedness,

dark-ness before one’s eyes, or a feeling of

emptiness

The duration of vertigo may point to a

particular group of possible

etiolo-gies An attack duration of a few

sec-onds is typical for all forms of

posi-tional vertigo, minutes for

vertebro-basilar TIA or migraine, hours for

M ´eni `ere’s disease, and days for

vesti-bulopathies such as vestibular

neuri-tis or labyrinthine infarction

Persis-tent vertigo is rarely of vestibular

ori-gin

Positional vertigo occurs only in

cer-tain positions of the head or body, or

only during certain changes of

posi-tion Concomitant auditory symptoms

indicate a peripheral vestibular

etiol-ogy, while visual abnormalities

indi-cate cortical pathology (in the case of

diminished visual acuity or a field

de-fect) or a brainstem process (in the

distur-Gait unsteadiness due to

polyneuro-pathy or posterior column diseasemay be perceived by the patient asvertigo This symptom worsens whenthe eyes are closed or in the dark, just

as in the rarer case of a bilateral tibular deficit Characteristic of thelatter is a perception of the environ-ment as being in motion – dancing or

ves-sliding away (oscillopsia, cf p 646) Psychogenic vertigo, of which the

most common type is phobic posturalvertigo, should be suspected in pa-tients with obsessive-compulsive orhysterical personality traits com-

bined with anxiety or phobias

(agora-phobia, fear of falling, fear of death),and in patients complaining of

situation-dependent vertiginous tacks (e.g., only on bridges or on stair-

at-cases, while driving on the highway,etc.)

Physical Examination of the Patient with Vertigo (298e)

Pathologic nystagmus is the most portant sign to be looked for (cf Ta-

im-bles 9.5 and 9.13, and Fig 9.16) As

al-ready mentioned on p 643, the amination must be carried out withthe patient wearing Frenzel goggles,

ex-or in the dark with an infrared devicefor visualization Visual fixation couldotherwise suppress vestibular nys-tagmus, producing falsely negativefindings

Spontaneous vestibular nystagmus.

This is characterized by a horizontalbeat with a small torsional compo-

694 9 Diseases Affecting the Cranial Nerves

Table 9.15 Questions for history-taking in

a patient complaining of dizziness

Circumstances in which dizziness first

arose?

Quality of dizziness?

Episodic or continuous?

Single or multiple episodes?

Duration of episode (seconds, minutes,

hours, days)?

In what bodily position(s) is dizziness

worst?

Do particular changes of position

in-duce dizziness (bending forward, lying

down, turning in bed, looking up or

down)?

Auditory symptoms such as tinnitus,

hearing loss, ear pain or pressure?

Visual symptoms (blurring, diplopia,

phosphenes)?

Oscillopsia, spontaneous or induced by

particular head positions?

Effect of darkness or closing eyes on

dizziness?

Autonomic symptoms (nausea,

vomit-ing, diaphoresis)?

Situational dizziness (in a department

store, in a crowd, on a staircase)?

Neurologic symptoms, such as

dyspha-gia, dysarthria, sensory disturbances on

the face or body, or weakness of the

face, arm, or leg?

History of migraine?

Medications?

nent (see Fig 9.16) It is provoked by

gaze in the direction of the beat It

can be graded in terms of severity

(Alexander grades I, II, and III) An

at-tempt should also be made to

pro-voke vestibular nystagmus by neuvers such as shaking the head;any nystagmus produced in this way

ma-is abnormal and should be ered a form of perhaps very mildspontaneous vestibular nystagmus.Finally, the examiner should look forother forms of nystagmus, such as

consid-gaze-evoked, upbeat, downbeat, purely horizontal, or diagonal nystagmus,

and note whether the beat is gate or dissociated

conju-Positional nystagmus. Nystagmus

may arise only when the head is in certain positions; as a typical exam-

ple, when the head is positioned withthe right ear down, there may be anonfatigable, left-beating nystagmus.Note the rule of thumb that positionalnystagmus of this type beats towardthe higher ear, or, in equivalent terms,away from the ground – it is

“ageotropic.”

Positioning nystagmus On the other

hand, nystagmus may be present only

transiently after a shift of position (cf.

the above discussion of positionalvertigo, p 694) Nystagmus of thistype must be sought with the Hall-pike maneuver, illustrated in

Fig 9.29 The patient is shifted from

the sitting position to the supine sition with the head 30° downwardand to the left or right Nystagmustypically appears after a latency of afew seconds, increases in intensityover a few seconds, then diminishesand disappears The patient simulta-neously experiences intense rotatoryvertigo, perhaps accompanied bynausea The nystagmus is mainly ro-tatory, clockwise when the head isdown and to the left and counter-clockwise when the head is down and

po-to the right If the patient looks po-Disturbances of the Vestibulocochlear Nerve 695

from the sitting position (a)

to the supine position withthe head hanging down and

to the right (b) or left (c)

Po-sitioning vertigo manifestsitself in counterclockwise ro-tating nystagmus when thehead is down and to the right

(d), clockwise rotating

nystag-mus when the head is down

and to the left (e) The

nys-tagmus may beat vertically ifthe subject looks away fromthe floor The intensity of nys-tagmus and vertigo first in-creases and then decreaseswithin a few seconds

ward the floor, the nystagmus

be-comes purely rotatory; if the patient

looks at his own nose (away from the

floor), it beats upward This type of

positioning nystagmus generally

fa-tigues rapidly and can often be

elic-ited only if the patient is allowed to

rest for a while before the test is

> Elicitation of vestibular nystagmus.

Vestibular nystagmus is normallysymmetrically elicitable and visible

to the examiner when the patient,

696 9 Diseases Affecting the Cranial Nerves

Head down and to the right Head down and to the left

c

d, e

Fig 9.29c–e

wearing Frenzel goggles, is rotated

back and forth on a swivel chair

This test is not very sensitive, but

any asymmetry or absence of

nys-tagmus indicates uni- or bilateral

vestibular pathology

> Caloric vestibular testing provides a

more sensitive indication of a

ves-tibular deficit The patient lies with

the body and head rotated 30° from

the supine position, or else sits

up-right with the head tilted back 60°

If the left ear canal is then irrigated

with 100–200 mL of water at room

temperature, or 5–10 mL of ice ter, horizontal nystagmus normallyappears, beating to the right Thepatient points to the left on the

wa-B ´ar ´any pointing test (see below)and tends to fall to the left Vertigoand nausea are simultaneously in-duced Irrigation with warm water(44°C) produces the opposite ef-fects Absence of these reactionsindicates that the labyrinth is un-excitable or that its connection tothe brainstem is interrupted Tym-panic perforation should alwaysDisturbances of the Vestibulocochlear Nerve 697

be ruled out by otoscopy before

caloric testing is performed

> Electronystagmography allows

standardized evaluation of

differ-ences between the caloric

re-sponses of the right and left ears It

is even more informative when

combined with the use of a

computer-controlled swivel chair

> The head thrust maneuver

(Hal-magyi-Curthoys test) (376a) is

used to test the oculovestibular

re-flex in the horizontal plane and is

thus a test of the horizontal

semi-circular canal The examiner

rap-idly turns the patient’s head to one

side while the patient looks at the

examiner’s nose The patient’s eyes

should remain fixed on the

exam-iner’s nose the entire time,

includ-ing while the head is turninclud-ing,

be-cause the oculovestibular reflex is

very fast (p 653) If the labyrinth is

partially or totally dysfunctional,

the eyes go along with the head as

it is rotated, and, as soon as the

head comes to a stop, a saccade

brings the eyes back into fixation

on the examiner’s nose (Fig 9.30).

If the right labyrinth is

dysfunc-tional, the saccade is to the left

af-ter a head thrust to the right; if the

left labyrinth is dysfunctional, the

saccade is to the right after a head

thrust to the left.

> Walking with the eyes closed in the

presence of a vestibular deficit

re-sults in the appearance (or

worsen-ing) of gait unsteadiness or a

con-stant deviation to one side The

pa-tient is asked to walk toward the

examiner from a distance of 5 m

This test is performed three times

in succession If there is an

asym-metry of vestibular tone, the

pa-tient’s gait will consistently deviate

to one side Care should be taken to

eliminate brightness cues that thepatient might see even with theeyes closed (e.g., the examinershould not stand in front of thewindow on a sunny day)

> Positional and pointing tests

(Fig 9.31) and Unterberger’s

step-ping test can also reveal deviation

to one side In the Unterberger test,the patient walks in place for1–3 minutes Rotation or change ofposition is no more than slight inthe normal situation, but marked ifthere is an asymmetry of vestibulartone Threshold values for a posi-tive test are 1 m forward move-ment and 40–60° of rotation after

50 steps

> The Babinski-Weil walking test is

analogous to the above The patientcloses his eyes and walks repeat-edly two steps forward and twosteps backward; any rotation or lin-ear displacement implies a vestibu-lar deficit

> Otoscopy and a complete cal and general physical examina- tion complete the work-up The ex-

neurologi-aminer should remember to sure the blood pressure in botharms, and with the patient lyingand sitting, to rule out vascularpresyncope due to orthostatic hy-potension or subclavian steal syn-drome (p 554)

mea-> Patients with oscillopsia depending

on head position or whose vertigoworsens in the dark should un-dergo caloric vestibular testing, asdescribed above

> A fistula test should be performed whenever a perilymph fistula is sus-

pected, as well as routinely inchronic otitis Digital pressure onthe tragus suffices, in some cases,

to provoke the symptoms; in othercases, a pressure wave of graded in-

698 9 Diseases Affecting the Cranial Nerves

Deficit of right horizontal semicircular canal

text; adapted from Huber.)Disturbances of the Vestibulocochlear Nerve 699

b

Fig 9.31a, b Modified B´ar´any pointing test.

a The patient points

with her extended dex fingers to the ex-aminer’s index fin-gers

in-b The patient closes her

eyes Deviation to oneside or the other indi-cates asymmetry ofvestibular tone

tensity can be created in the external

ear canal by stepwise inflation of a

Politzer balloon A positive test is

as-sociated with the appearance of

Hen-nebert’s sign (vertigo and nystagmus

to the affected side) This test detectsfistulae of the lateral semicircular ca-nal (912)

700 9 Diseases Affecting the Cranial Nerves

Differential Diagnosis

A complete history and physical

ex-amination usually enables the

differ-entiation of vestibular from

nonvesti-bular vertigo, and the classification of

vestibular vertigo as central or

pe-ripheral Details are given in

Ta-ble 9.16.

Ancillary Tests

Electronystagmography is useful for

the objective documentation of lomotor disturbances of vestibular or-igin It enables the quantitative as-sessment of abnormal findings butnonetheless does not obviate theneed for clinical examination In par-

ocu-Table 9.16 Differentiation of peripheral vestibular, central vestibular, and nonvestibular

vertigo

Peripheral vestibular (labyrinth, nerve)

Central vestibular Nonvestibular

Nausea, vomiting,

Quality of vertigo Directional Moderately

af-in one direction,not always to af-fected side

No directional viation

de-Head thrust test

(Halmagyi test) Returning saccadeafter head thrust

to affected side

Returning saccadeoften evident Normal

Caloric excitability Diminished on the

affected side Usually normal Normal

bilat-Usually no effect Worsening if

pro-prioception is paired

ab-ticular, positioning nystagmus is

more readily detected clinically than

by electronystagmography Other

an-cillary tests are of analogous

useful-ness in vestibular as in auditory

dys-function – for imaging studies and

lumbar puncture, see above (p 77).

Treatment of Vertigo

Vertigo is treated according to its

eti-ology, as discussed below

Treatment

Nonspecific vertigo, particularly in

the elderly, may be relieved to

some extent by cinnarizine, calcium

antagonists such as flunarizine, or

co-dergocrine Physical therapy and

ball games may also be useful

means of vestibular training

Diseases Causing Prominent

Vertigo

Acute Vestibular Dysfunction

Commonly used synonyms for the

syndrome of acute vestibular

dys-function are “vestibular neuritis,”

“acute vestibulopathy,” and

“labyrin-thitis” or (if hearing is also affected)

“cochleolabyrinthitis.”

Pathogenesis

The same clinical syndrome is

pro-duced by any acute, unilateral

vestib-ular disturbance, be it of vascvestib-ular,

in-fectious, or neoplastic origin A small

number of autopsy studies support

the hypothesis that the cause is

usu-ally infectious Further evidence

comes from the epidemic appearance

of this syndrome and from the fact

that it mainly affects middle-aged

adults without significant vascular

risk factors Neurophysiological

in-vestigation reveals an asymmetry ofvestibular tone, in which the vestibu-lar neurons on one side fail to dis-charge spontaneously

Clinical Features

Typical features include:

> acute rotatory vertigo,

> a tendency to fall to the side of theaffected ear,

> vegetative symptoms (nausea, miting, diaphoresis)

vo-Movement of the head worsens thesymptoms to such a degree that pa-tients initially cannot get out of bed.Abnormal auditory sensations orhearing loss are exceptional (unlike in

M ´eni `ere’s disease) Examination veals horizontal spontaneous nystag-mus with a rotatory component,rightward and counterclockwise or

re-leftward and clockwise (see Fig 9.16).

The nystagmus beats away from theside of the lesion and can be sup-pressed by visual fixation or en-hanced by lying with the affected eardown Ocular pursuit movements andsaccades are normal The caloric re-sponse is diminished or absent on theaffected side

Course and Prognosis

The initial vertigo subsides within afew days The patient can often getout of bed on the first day, within afew days at most At this point, grade

I or II nystagmus and deviation canstill be found on positional testing,with the Unterberger test, and whenthe patient walks with eyes closed,but the patient is less nauseated andhas stopped vomiting A few dayslater, all that remains of the initialsymptoms is a mild unsteadiness ofstance and gait, particularly whenthe head is suddenly moved At this

702 9 Diseases Affecting the Cranial Nerves

point, nystagmus can usually be

elic-ited by head shaking All clinical

symptoms resolve 1–6 weeks after

their onset Most patients experience

vestibular neuritis only once, but

sin-gle or multiple recurrences in the

en-suing years are not unusual The

reso-lution of symptoms may be due

ei-ther to recovery of the temporarily

af-fected vestibular organ, or to central

compensation for a permanent

pe-ripheral deficit

Ancillary Tests

No further testing is required if the

symptoms are sufficiently

character-istic, but may be indicated if atypical

features are found in the clinical

his-tory or physical examination, or if the

symptoms persist

Differential Diagnosis

Acute vestibular dysfunction has

vari-ous causes

M´eni`ere’s disease causes attacks that

last for hours and are accompanied

by hearing loss and tinnitus

Circula-tory disturbances may cause

tran-sient or permanent ischemia of the

labyrinth, brainstem, or cerebellum

(p 172)

A cerebellar hemispheric infarct is

usu-ally accompanied by clinicusu-ally

evi-dent ataxia on the side of the lesion

(which is not found in a vestibular

deficit) Likewise, brainstem infarcts

produce vestibular as well as other

neurologic deficits

Tumors (acoustic neuroma,

meningi-oma, glomus tumor, etc., p 68)

usu-ally cause slowly progressive vertigo

Trauma is usually evident from the

clinical history (e.g., petrous fracture)

Isolated acute attacks of vertigo can

occur in migraine (p 805).

Otitis media, whose clinical hallmark

is conductive hearing loss, may

ex-tend to other pneumatized portions ofthe petrous bone (otomastoiditis) andsecondarily cause vestibular dysfunc-tion A mixed vestibulocochlear defi-cit is usually found in such cases In

malignant otitis, the infection spreads

into the subarachnoid space and fects other cranial nerves as well.Specific infections, such as mumpsand measles, can cause both vestibu-lar and auditory deficits, and syphilis,borreliosis, and tuberculosis usuallyaffect other cranial nerves as well.Herpes zoster oticus usually causesfacial nerve palsy and vesicles on thepalatal arch and external auditory ca-nal (Ramsay Hunt syndrome, pp 677and 824)

af-Cogan syndrome is characterized by

the combination of interstitial tis with sudden hearing loss and ves-tibular dysfunction (983) While thekeratitis heals relatively quickly, theauditory and vestibular deficits per-sist The disease usually affects thelabyrinth on both sides and is typi-cally accompanied by aortitis An au-toimmune pathogenesis is presumed

kerati-Treatment

Antivertiginous and antiemeticmedications are given in the acutephase, among them antihistamines(e.g., promethazine), phenothia-zines (e.g., thiethylperazine), ben-zodiazepines, and neurolepticssuch as dihydrobenzperidol or sco-polamine

These medications may need to

be given intramuscularly, nously, or per rectum, rather thanorally Once the patient has stoppedvomiting, the medications should

intrave-be discontinued as soon as possible,

so that the vestibular compensationwill not be delayed or prevented.Disturbances of the Vestibulocochlear Nerve 703

If the patient can tolerate them,

oc-ular fixation exercises should be

performed, as well as head turning

and static and dynamic equilibrium

exercises Ball games are a form of

dynamic equilibrium exercise

The underlying cause should be

treated, as far as possible

M´eni`ere’s Disease

Tinnitus, hearing loss, and vertigo

typify this disease, which most

com-monly affects men and women

be-tween the ages of 30 and 60

Pathogenesis

M ´eni `ere’s disease is due to

endolym-phatic hydrops The membranes

sepa-rating endolymph from perilymph

rupture at irregular intervals, causing

an abrupt rise in the potassium

con-centration of the endolymph, which,

in turn, impairs neuronal function

until the physiologic concentration is

restored Endolymphatic hydrops

may be idiopathic or a late

complica-tion of a labyrinthine disease of some

kind, such as Mondini’s inner ear

dys-plasia, viral, bacterial, or spirochetal

infection, or petrous fractures An

au-toimmune mechanism has also been

postulated

Clinical Features

A typical attack consists of:

> a sensation of pressure and fullness

in the ear,

> hearing loss,

> tinnitus, and

> severe rotatory vertigo

In most patients, the pressure

sensa-tion, hearing loss, and tinnitus

pre-cede the vertigo in the manner of an

aura, but are nonetheless most severe

during the attack itself The hearingloss at first mainly involves the high-frequency range, but can spread tothe entire frequency spectrum afterrepeated attacks Vertigo is usually sosevere that the patient cannot stand

up or walk, and it is accompanied bynausea, vomiting, and diaphoresis.Other clinical features are those ofacute vestibular dysfunction, as de-scribed above Attacks resolve within

a few hours, though the patient mayremain mildly vertiginous and feelmildly unwell for several days there-after

Lermoyez syndrome In this variant of

M ´eni `ere’s disease, hearing improvesduring the attacks of vertigo, but thepathogenesis, clinical features, andtreatment are otherwise typical

Course and Prognosis

There are, at first, no symptoms in tween attacks The attacks repeat ev-ery few weeks or months Once a few

be-of them have occurred, most patientsdevelop tinnitus and slowly progres-sive hearing loss, at first for low fre-quencies, and then for higher fre-quencies as well Labyrinthine atro-phy is the presumed cause In somepatients, the hearing loss progresses

to complete deafness, and vestibularfunction can be lost as well Bilateraldisease is not uncommon (133) and isseen in 15% of cases after 2 years, and

in 30–60% after 10–20 years theless, the course is generally be-nign, in that 80% of cases remit spon-taneously in 5–10 years

None-Diagnosis

The diagnosis of M ´eni `ere’s disease isbased on the clinical triad describedabove The administration of hyper-osmolar substances, such as glycerin

704 9 Diseases Affecting the Cranial Nerves

and urea, may transiently improve

hearing, which supports the

diagno-sis There is no other specific test for

the disease

Treatment

The acute attacks are self-limited

As in the syndrome of acute

vestib-ular dysfunction, they can be

treated symptomatically with

anti-vertiginous and antiemetic agents.

The goal of interval therapy is a

re-duction in the frequency of the

at-tacks, so that hearing can be

pre-served Betahistine has been shown

to be effective for this purpose

(667)

Some patients benefit from a

low-sodium diet (1–2 g/day for at least

2 months, longer if effective)

Surgical treatment may be

indi-cated in carefully selected,

medi-cally intractable cases, though it

should be borne in mind that the

disease is often self-limiting, and

also that it may later affect the

other side in 30–60% of cases

Se-lective vestibular neurectomy can be

performed in patients with

pre-served hearing, labyrinthectomy in

those that are already deaf in the

affected ear

Pharmacologic destruction of the

vestibular apparatus is a less

inva-sive treatment that can be of

bene-fit in some cases Vestibulotoxic

aminoglycosides such as

strepto-mycin or gentamicin are used

Transverse Fracture of the

Petrous Bone

These fractures cause acute, complete

vestibular dysfunction with rotatory

vertigo, vomiting, inability to stand,

deafness with or without tinnitus,

fa-cial nerve palsy, and, in about half ofall patients, otorhinoliquorrhea Oto-scopy reveals a dark discoloration ofthe eardrum due to an accumulation

of blood behind it There is markedspontaneous vestibular nystagmus,and the traumatized ear is deaf TheWeber test is lateralized to the oppo-site side Antibiotics are often given

to prevent labyrinthitis and early andlate post-traumatic meningitis

Perilymph Fistula

This condition arises from a rupture

of the oval or round window orthrough erosion of the bony semicir-cular canal by an osteolytic process Itmay present clinically in a variety ofways, including:

> purely vestibular vertigo,

> purely cochlear hearing loss,

> tinnitus,

> or a combination of the above.Vertigo is the most common symp-tom, generally in the form of episodicrotatory or positional vertigo The di-agnosis is based on the clinical his-tory, or, less commonly, on the detec-tion of an osteolytic process (such aschronic otitis with cholesteatoma).Particular entities to be borne inmind during history-taking includehead trauma, barotrauma (flying, div-ing), Valsalva maneuvers (e.g., duringcoughing, blowing the nose, orweight-lifting), or surgical proce-dures on the stapes The fistula test isusually positive (p 698)

Tullio’s phenomenon is also

demon-strable in many cases: loud acousticstimuli (90 dB or above) induce ves-tibular manifestations such as ver-tigo, nystagmus, oscillopsia, and ves-tibulospinal dysfunction Most fistu-lae heal spontaneously with bedrestDisturbances of the Vestibulocochlear Nerve 705

with slight elevation of the head, but

a few require surgical repair

Bilateral Vestibular Dysfunction

(55)

The typical symptoms of bilateral

vestibular dysfunction are:

> gait unsteadiness that worsens

when the eyes are closed, on

un-even ground, or in the dark; and

> oscillopsia depending on head

po-sition (e.g., bobbing of the horizon

when the patient walks)

On clinical examination, the head

thrust test is abnormal bilaterally,

and caloric testing reveals diminished

or absent excitability of the vestibular

apparatus bilaterally

Bilateral vestibular dysfunction can

arise either with or without hearing

loss It can be caused by any disease

or condition that affects both

laby-rinths or both vestibular nerves

si-multaneously, including:

> ototoxic medications

(streptomy-cin, gentamicin),

> bilateral M ´eni `ere’s disease,

> residual deficits after meningitis or

Physiotherapeutic exercises are

per-formed to train head movement in

all three dimensions Such

exer-cises promote the strengthening of

nonvestibular – i.e., oculocephalic

and proprioceptive compensatory

mechanisms, with resulting

im-provement of stance and gait

Positional and Positioning Vertigo

The terms “positional vertigo” and

“positioning vertigo” refer to any type

of vertigo that arises only when thehead is in a certain position, or onlywith certain movements of the head.Positional and positioning vertigohave diverse causes

The most common type of ing vertigo – indeed, of vertigo in

position-general – is benign paroxysmal tioning vertigo, or BPPV (see below) Central positional nystagmus typically

arises as soon as the head is tioned to lie on one side, does not fa-tigue, and beats toward the upper ear– i.e., to the left ear when the patient

posi-is lying on the right side, and viceversa (Other types of beat may also

be encountered.) There is often little

or no accompanying vertigo The sion is always in the brainstem orvestibulocerebellum and may be of

le-any type Downbeat nystagmus, too,

may be worst with certain positions

of the head, typically when the tient is supine and the head hangsdown (p 651)

pa-Another type of central positionalnystagmus arises only with certainmovements of the head and is charac-terized by rotatory vertigo with nys-tagmus, truncal ataxia, and usuallythe inability to walk The lesion ismost commonly in the roof of thefourth ventricle, generally a tumor orhemorrhage of the fourth ventricle orvermis

In the healing phase of acute lopathy, too, vertigo may be presentonly when the labyrinth is stressed –i.e., only with certain head move-ments

vestibu-706 9 Diseases Affecting the Cranial Nerves

Benign Paroxysmal Positioning

Vertigo (BPPV) (Cupulolithiasis,

Canalolithiasis) (237, 856)

This disorder consists of transient,

se-vere vertigo induced by changes in

the position of the head It affects

persons of any age, women

some-what more commonly than men

Pathogenesis

For anatomic reasons, detritus, such

as particles shed by the otolith

mem-brane, tends to land in the posterior

semicircular canal It may be caught

on the cupula (cupulolithiasis) or

float freely in the endolymph

(canalo-lithiasis) Excessive loading of the

cu-pula in the first case, or the increase

in the overall specific gravity of the

endolymph in the second case (which

is much more common), leads to an

excessive post-rotatory response

when the head is turned in the plane

of the posterior semicircular canal of

the affected ear

Etiology

Paroxysmal positioning vertigo may

be a sequela of head trauma, viral

neurolabyrinthitis, or, in rarer cases,

other processes affecting the

laby-rinth In most cases, however, no

spe-cific etiology or precipitating event

can be identified

Clinical Features

Vertigo typically arises when the

pa-tient turns in bed, lies down, sits up,

stands up, bends over, or looks

up-ward Attacks of vertigo often occur

when the patient attempts to pick an

object up off the floor or from a high

or low shelf Severe rotational vertigo

mostly lasts no more than a few

sec-onds, never more than a minute,

though the accompanying vegetative

phenomena, such as queasiness, maylast longer Patients are often so dis-tressed by the first attack that theyseek medical help immediately On

examination, the Hallpike maneuver

(best performed with Frenzel

gog-gles) produces a mainly rotatory tagmus that is counterclockwise

nys-when the head hangs downward and

to the right, clockwise when it hangsdownward and to the left (cf

Fig 9.29) If the patient looks away

from the floor (i.e., toward his ownnose), the nystagmus may beat purelyvertically When the patient sits upagain, nystagmus occurs in the down-beating direction Both on lying downand on sitting up, it occurs with a la-tency of one or more seconds, rapidlyreaches peak intensity, then declinesand disappears over a further10–40 seconds Vertigo takes a paral-lel time course The nystagmus andvertigo are more severe when the pa-tient is positioned on the side of theaffected labyrinth They become lesspronounced on repeated testing (ha-

bituation), eventually becoming

un-elicitable unless the patient is given abrief rest between tests

Diagnostic Evaluation

The diagnosis is based solely on theclinical history and physical examina-tion Ignorance of this conditionamong physicians sometimes leads tothe performance of unnecessary CTand MRI scans, Doppler ultrasonogra-phy, and various cardiologic studies

Differential Diagnosis

Positional and positioning vertigo, as

we have seen, may also be a sign of

perilymph fistula or M´eni `ere’s disease,

as well as of labyrinthine atelectasis or

a central lesion Precise observation of

the clinical manifestations generallyDisturbances of the Vestibulocochlear Nerve 707

enables a clear-cut differentiation of

BPPV from other causes of positional

and positioning vertigo

Neurovascu-lar compression syndromes have also

been reported to cause “disabling

po-sitional vertigo,” but this entity is, in

our opinion, poorly definable at best

Treatment

Specific positioning maneuvers (the

Semont and Epley maneuvers) can

be used to flush the detritus out of

the posterior semicircular canal

and relieve vertigo immediately

(132, 282a) The patient himself

can also bring about relief, though

not immediately, by repeatedly

putting himself in the position that

induces vertigo (Brandt-Daroff

ma-neuver) Patients initially

disin-clined to use the last-named

method can be persuaded of its

usefulness by a test-run in the

doc-tor’s office In our experience, the

Epley maneuver is the best of the

three, with a success rate above

90% (Fig 9.32).

Canalolithiasis of the horizontal

semi-circular canal This entity is analogous

to the more common disorder just

described, which affects the posterior

semicircular canal (54, 572) It is

char-acterized by positioning vertigo and

horizontal nystagmus that arise when

the patient turns from the supine to

the lateral decubitus position

Canalolithiasis of the anterior

semicir-cular canal is even rarer than that of

the horizontal semicircular canal The

anterior canal lies in the same plane

as the contralateral posterior canal

The symptoms of anterior

canalolithi-asis therefore resemble those of the

more common posterior

canalolithia-sis If the left side is involved (for ample), vertigo is induced when thepatient lies down with the headturned to the right The nystagmus isdown-beating and torsional, and thenbeats upwards when the patient sits

ex-up again This type of canalolithiasis,like the other types, can be treatedwith specific positioning maneuvers

Central Vertigo

Central (vestibular or nonvestibular)vertigo is usually accompanied bysome form of oculomotor distur-bance, as mentioned on p 630 Thefindings in such patients include stra-bismus, diplopia, central nystagmus,impairment of head-eye coordinationand the oculovestibular reflex, oscil-lopsia, ataxia, and other brainstemand cerebellar signs

Vertebrobasilar insufficiency can

pro-duce shorter or longer attacks of ther peripheral or central vertigo(p 198)

ei-Vestibular epilepsy, a rare central

cause of vertigo, is due to a temporal

or parietal lesion (490) Focal charges in the posterior portion of thesuperior temporal gyrus (primaryvestibular cortex) or in the intrapa-rietal gyrus (vestibular associationcortex) generate vertigo, which can

dis-be either a nonspecific feeling or asensation of turning, leaning, or fall-ing to one side Nystagmus may bepresent or absent These patientsusually also suffer from complex par-tial and grand mal seizures, of whichvertigo may be the aura

Migraine and Vertigo (p 804)

Vertigo may be the expression of graine (so-called “vestibular mi-graine”) This condition is easy to di-

mi-708 9 Diseases Affecting the Cranial Nerves

agnose when vertigo appears as an

aura preceding a typical headache,

with or without other accompanying

manifestations of basilar migraine

The diagnosis is much more difficult

when the vertigo occurs without

headache, as is the case in benign,

re-current vertigo in adulthood (675).

This disorder, which affects persons

suffering from migraine, consists of

recurrent attacks of vertigo and

dyse-quilibrium lasting minutes to hours

and sometimes accompanied by

nau-sea, spontaneous nystagmus, and

po-sitional vertigo, but no other

vestibu-lar or neurologic manifestations The

clinical examination is normal in

be-tween attacks

Benign, recurrent vertigo in childhood

is another disorder that can be

con-sidered to be a migraine equivalent It

affects children between the ages of 1

and 4 years (rarely older) The attacks

last seconds to minutes and consist of

disabling vertigo and ataxia,

nystag-mus, nausea, vomiting, sweating, and

pallor, without headache, and

with-out impairment of consciousness In

many cases, these attacks are

re-placed by another form of migraine as

the patient grows older

Treatment

Prophylactic treatment, such as is

used to prevent migraine

head-ache, is often beneficial in patients

suffering from vertigo as a migraine

equivalent, or from recurrent

ver-tigo of indeterminate etiology

Medications and Vertigo (133)

The list of medications that can cause

vertigo is long, and the pathogenetic

mechanisms are varied Medications

can induce vertigo by way of

cerebel-lar dysfunction, oculomotor bances, positional vertigo and nystag-mus, direct effects on the labyrinth,

distur-or systemic cardiovascular effects

Visually Induced Vertigo

Vertigo can be induced by a suddenchange of refraction, as after a change

of spectacle prescription, or a switch

to bifocal lenses or special spectaclesafter cataract extraction Vertigo canalso be induced by diplopia or extra-ocular muscle palsies that impair sta-bilization of the visual image on theretina when the head is moving A vi-sual field defect can impair visualperception of movement of the bodyrelative to the environment; acute vi-sual field defects can thus causevisual-vestibular “mismatch,” andhence vertigo

Visual hallucinations can also cause vertigo, as can tilted and inverted vi- sion, types of visual illusion produced

by lesions of the occipital lobes andcerebellar hemispheres, probablythrough a vestibular mechanism

Vertigo Due to Impaired Proprioception

Spinal cord lesions that involve theposterior columns (p 441) and poly-neuropathies (p 581) may producevertigo, or simply unsteadiness ofstance and gait, as their principalsymptom because of impaired pro-prioception These problems worsenDisturbances of the Vestibulocochlear Nerve 709

Lateral

Posterior

lympha- tic duct

Endo-Posterior

Lateral

Anterior

Posterior Lateral Anterior

710 9 Diseases Affecting the Cranial Nerves

when visual input is removed – i.e., in

the dark or when the patient’s eyes

are closed

Psychogenic and Phobic Postural

Vertigo (133)

Vertigo in patients suffering from

anxiety, depression, hysteria or

psy-chosis, or in the aftermath of (bodily)

trauma, may lack an organic basis or

an objective correlate on

neuro-otologic examination Generally,

however, at least some organic

com-ponent can be identified – e.g., a

tran-sient post-traumatic otolithic

dys-function that assumes a life of its own

as a later, psychogenic development

Acrophobia and agoraphobia are types

of psychogenic vertigo Affected

indi-viduals feel unsteady and out of

bal-ance, and may suffer panic attacks,

when they find themselves on a

(pos-sibly very mild) elevation, or in a

wide open space or public square

Phobic postural vertigo is practically

always associated with specific

situa-tions – e.g., walking across a bridge,

driving a car, empty spaces,

depart-ment stores, restaurants, theaters

These situations induce unsteadiness

of stance and gait, without any

objec-tive correlate Any mode of physical

support, even a relatively flimsy one

such as leaning against a wall or on

the armrest of a chair, may suffice to

restore a sense of security Patients

P Fig 9.32

S The patient sits on the examining table

1 The patient is rapidly shifted to the

su-pine position with the head hanging 30°

downward and 45° to the affected side

2 The head is rotated to the unaffected

side

3 The head and body together are further

rotated to the unaffected side until

the body is in the lateral decubitus

position and the head looks toward thefloor

4 The patient sits up by raising the trunklaterally, keeping the head turned to theside

5 The head is inclined

Any one of these steps can induce vertigo.There should thus be a pause of 20–30 sec-onds between steps, or as long as it takesfor vertigo to subside

with this condition are usuallygripped by a fear of falling and hurt-ing themselves Such fears may result

in full-blown panic attacks, and ipatory anxiety with regard to suchsituations can finally result in a con-ditioned reflex that markedly limitthe patient’s ability to participate inand enjoy life

antic-Cardiovascular, Endocrine, Metabolic, and Hematopoietic Diseases Causing Vertigo

Any hemodynamic disturbance thatimpairs circulation in the brain, orany metabolic disturbance that limitsits energy supply, can cause promi-nent vertigo in the absence of anypositive findings on neuro-otologicexamination

Vertigo is a frequent manifestation of

orthostatic hypotension, generally

oc-curring when the patient rises from alying or sitting position, or after pro-longed standing This type of vertigo

is accompanied by tinnitus, darknessbefore the eyes, diaphoresis, yawning,and dyspnea

The other types of vertigo in this classare independent of bodily position

Cardiac arrhythmia produces brief

dazedness and darkness before theeyes or more severe manifestations

up to and including Adams-Stokes tacks with loss of consciousness In

at-vasovagal reactions, vertigo is

asso-Disturbances of the Vestibulocochlear Nerve 711

Fig 9.33 Curtain sign.

In right geal nerve palsy, elicita-tion of the gag reflex isfollowed by pulling ofthe palate and posteriorpharyngeal wall to theunaffected left side

glossopharyn-ciated with hypotonia and

bradycar-dia Vertigo due to elevated

intratho-racic pressure – e.g., during coughing

– is due to the resulting intracranial

hypertension and transient cerebral

hypoperfusion (644) Vertigo due to

arterial hypertension is usually

ac-companied by headache Nonspecific

vertigo is also a major complaint of

many patients with vegetative

dysto-nia and hyperventilation tetany; such

patients also commonly suffer from afainting tendency, depression, and

headaches Vertigo due to endocrine disorders is generally accompanied by

fatigue, lethargy, fainting tendency,

and hypoglycemia Finally, anemia, hyperviscosity syndromes, electrolyte disturbances, vitamin B 12 deficiency,

and other diseases may also lie hind nonspecific vertigo with nega-tive neuro-otologic findings

be-Glossopharyngeal and Vagus Nerve Dysfunction

Anatomy and Examining Techniques

The reader is assumed to be familiar

with the anatomy and examining

techniques of CN IX and X

Clinical Features

Lesions of the ninth and tenth cranial

nerves cause dysphagia and

hoarse-ness Examination reveals a sensory

deficit on the palatal arch and

poste-rior pharyngeal wall of the affected

side, unilateral vocal fold paresis

(vis-ible by laryngoscopy), and the

“cur-tain sign,” in which the response to a

gag stimulus consists of a pulling of

the palatal arch and posterior

pha-ryngeal wall to the unaffected side

(Fig 9.33).

Causes Nuclear pareses Dysfunction of the

brainstem nuclei of cranial nerves IXand X is seen in syndromes of medul-lary dysfunction caused by vasculardisorders, tumors, encephalitis, ormultiple sclerosis

Nerve trunk lesions These may arise

in isolation or accompanied by cits of other caudal cranial nerves

defi-Basilar impression and skull base mors, including those that arise extra-

tu-cranially and grow inward from theepipharynx, are among the possible

causes An isolated unilateral deficit of

CN IX and X constitutes a separate

disease entity in children and

adoles-712 9 Diseases Affecting the Cranial Nerves

b

Fig 9.34a, b Testing the strength of the sternocleidomastoid (a) and trape- zius (b) muscles.

cents, mainly in boys, and has been

interpreted as a type of cranial

mono-neuropathy The affected patients

suddenly develop nasal speech and

mild dysphagia, in the absence of

pain or fever, and generally have

nor-mal CSF findings, without any

eleva-tion in protein concentraeleva-tion The

signs and symptoms regress

com-pletely in a few weeks or months in

practically all cases A basilar skull

fracture involving the jugular

fora-men may produce deficits of the

cra-nial nerves that traverse it (IX, X, XI)

(“syndrome du trou d ´echir ´e post

´e-rieur,” Vernet-Siebenmann

syn-drome) Similar findings are

pro-duced, on occasion, by herpes zoster(484), cerebral venous sinus throm-bosis, or torticollis, or indeed sponta-neously, with a good prognosis for re-covery A vascular mechanism pre-sumably underlies such benign andfully reversible deficits Tapia syn-drome (p 175), involving deficits of

CN IX, X, and XII, can also be produced

by an (extracranial) carotid aneurysm,

or by carotid dissection (p 192)

Differential Diagnosis

These cranial nerve palsies must be

distinguished from the palatal lysis of diphtheria and from pseudo- paralytic myasthenia gravis.

para-Accessory Nerve Palsy

Anatomy

The reader is assumed to be familiar

with the anatomy of the accessory

nerve

Examination Technique (Fig 9.34).

Clinical Features

The deficit is purely motor Lesions

affecting the nerve in the lateral

cer-vical triangle paralyze only the

supe-rior portion of the trapezius,

produc-ing a shoulder drop, a scapular tilt,

and a weak shrug

More proximal lesions also paralyze

the sternocleidomastoid muscle, which

turns the head to the opposite side

The most common cause of an

iso-lated accessory nerve palsy is

iatro-genic injury, often incurred during

biopsy of a lymph node lying at the

posterior border of the

sternocleido-mastoid muscle (this complication

occurs after as many as

three-quarters of all such procedures!) The

mild motor impairment or shoulder

Accessory Nerve Palsy 713

pain on movement are generally not

noticed by the patient until a few

weeks later, when he or she begins to

use the arm again The findings

in-clude a shoulder drop, a scapular tilt,

and atrophy of the upper portion of

the trapezius, without any sensory

deficit and with preserved function

of the sternocleidomastoid muscle

(Fig 9.35).

Accessory nerve palsy can also be due

to anomalies of the craniocervicaljunction, tumors at the foramen mag-num, and the jugular foramen syn-drome It is accompanied by otherneurologic findings in such cases

714 9 Diseases Affecting the Cranial Nerves

Fig 9.36 Unilateral atrophy and ness of the tongue due to right hypo- glossal nerve palsy.

weak-Hypoglossal Nerve Palsy

Anatomy and Examining Technique

The reader is assumed to be familiar

with the anatomy and examining

technique of CN XII

Causes of Tongue Weakness

Central tongue weakness Central

tongue weakness is seen, for

exam-ple, as a component of hemiparesis in

acute stroke As the musculature of

the tongue has bilateral cortical

rep-resentation (176a), central tongue

weakness is usually mild and is soon

well compensated for by the intact

contralateral innervation Bilateral

central tongue weakness, however, as

in pseudobulbar palsy (p 384),

causes severe dysarthria and

dyspha-gia, and thus considerable functional

impairment The tongue is not

atro-phic The buccolingual apraxia and

oral diplegia of Foix-Chavany-Marie

syndrome were mentioned in an

ear-lier chapter (p 385)

Nuclear tongue weakness Nuclear

tongue weakness is most commonly a

component of true bulbar palsy due to

amyotrophic lateral sclerosis (p 434)

(cf Fig 3.10) It is also seen, together

with contralateral hemiparesis, after

a stroke affecting one side of the

me-dulla (Jackson syndrome).

Lesions of the hypoglossal nerve

(185a, 503a) (Fig 9.36) These may be

due to basilar skull fractures involving

the occipital bone – e.g., condylar

fractures (225b), basilar impression,

tonsillectomy (241), brainstem or

skull base tumors, or carotid

dissec-tion (527, 919) Reversible, isolated CN

XII palsy occasionally occurs after an

infection or without identifiablecause (816)

Further causes Pain in the tongue

may be due to local causes, such asneoplasia or infection, or to herpes

zoster Intractable burning of the tongue occurs in the elderly as a form

of glossodynia, without any knowncause (p 826) The paroxysmal pain

of trigeminal neuralgia may affect

one-half of the tongue (which ceives its sensory innervation from

re-CN V) Paresthesiae and transient

“falling asleep” of one-half of thetongue are found in the so-called

neck-tongue syndrome (313a) Painful trophic disturbances of the tongue can

be seen in isolation in giant cell itis, or accompanied by other deficits

arter-in other types of arteritis, such asSjögren’s syndrome (547a)

Hypoglossal Nerve Palsy 715

Multiple Cranial Nerve Palsies

Cranial Polyradiculitis

This type of radiculitis involving the

spinal nerve roots and the caudal

cra-nial nerves, particularly the facial

nerve, is considered an atypical form

of Guillain-Barr ´e syndrome (p 575)

It arises after a long prodrome

con-sisting of headache It usually

solves without treatment, though

re-currences months or years later are

not uncommon Pathologic study of

such cases has revealed

granuloma-tous inflammation of the perineural

meninges The pathophysiology of

Fisher syndrome (p 280) is

presum-ably similar

(Recurrent) Multiple Cranial

Nerve Palsies

These have been described in

sar-coidosis, Sjögren’s syndrome (946a),

carotid dissection (527, 919), and

pa-raproteinemia or dysproteinemia

(Bing-Neel syndrome), among other

conditions Multiple cranial nerve

palsies may be the initial

manifesta-tion of vasculitis or polyarteritis

no-dosa (as a component of Cogan

syn-drome, p 325)

Recurrent palsies of multiple cranial

nerves often occur without any

iden-tifiable cause (95) and are then

some-times designated Gougerot-Sjögren

syndrome (364) Brown-Vialetto-Laere

syndrome involves caudal cranial

nerve palsies in conjunction with

bi-lateral hearing loss and other

neuro-logic deficits (217)

Progressive Palsies of Multiple Cranial Nerves

These may be due to chronic gitis, meningeal carcinomatosis,syphilis, or AIDS (963) Bilateral cra-nial nerve palsies have been reported

menin-as a complication of poorly controlleddiabetes mellitus Bone conditionssuch as Paget’s disease and Albers-Schönberg marble bone disease cancause cranial nerve palsies as well.Trichlorethylene poisoning has beenreported to cause a trigeminal nervedeficit, accompanied by other cranialnerve deficits (p 612)

Garcin Syndrome

This syndrome affects the caudal nial nerves on one side It is usuallydue to a tumor of the skull base

cra-Rarer Causes

Progressive caudal cranial nerve cits in conjunction with impaired au-tonomic regulation (the result of acombined lesion of the carotid sinusand sympathetic chain) may be due

defi-to a thorotrasdefi-toma, perhaps not

be-coming symptomatic till years aftercarotid angiography with Thorotrast.(This radiographic contrast medium,consisting of thorium dioxide in dex-tran, has not been used for manyyears.) Caudal cranial nerve deficitsmay be due to osteomyelitis of the

skull base as a complication of nant otitis externa Another rare en- tity, the stylokeratohyoidal syndrome,

malig-is due to a developmental anomalyand is characterized by deficits of CN

V, VII, IX, and X, along with lateralcervical pain, dysphagia, and vertigo

716 9 Diseases Affecting the Cranial Nerves

10 Spinal Radicular Syndromes

Overview:

The spinal nerve roots contain both motor and sensory fibers, and spinalradicular lesions therefore produce both motor and sensory denervation ofthe structures they innervate The muscles innervated by the affected rootbecome weak and atrophic Weakness and atrophy are most evident inmuscles that receive most or all of their innervation from the affected root,less so in other muscles, including portions of the paravertebral muscula-ture The reflexes associated with the paretic muscles are diminished Sen-sory denervation produces a dermatomal, usually band-like zone of hypes-thesia, which, because of the overlap between neighboring dermatomes, isnot always easy to demonstrate

General Symptoms and Signs

Lesions of individual spinal nerve

roots are clinically characterized by

some, or all, of the features listed in

Table 10.1.

> Pain in the distribution of the

af-fected root (practically always

pre-sent in acute lesions)

Table 10.1 General manifestations of

spi-nal radicular lesions

Pain:

> Mainly in acute lesions

> Usually with dermatomal radiation

> Most severe in muscles innervated

partly or wholly by affected root

Spinal signs and symptoms:

> When the cause is acute and

spon-dylogenic

> Dermatomal sensory deficit (cf

der-matome chart, Fig 1.1) This may be

difficult to demonstrate in dicular lesions, because neighbor-ing dermatomes overlap It is easier

monora-to demonstrate with a noxiousstimulus than with light touch

> Paresis of muscles innervated by

the affected root Table 10.2 shows

the muscles innervated by each

root, and Table 10.3 shows the

muscles receiving most or all oftheir innervation from a singleroot

> Muscular atrophy is commonly

found, but usually less pronouncedthan in peripheral nerve lesions,and usually does not become visi-ble till ca 3 weeks after the lesionarises

> Fasciculations are rarely seen in

ra-dicular lesions

> Reflexes subserved by the affected

nerve root are diminished Some ofthe relevant intrinsic muscle re-flexes (proprioceptive reflexes) are

listed in Table 10.4, some of the

rel-evant extrinsic muscle reflexes

(ex-teroceptive reflexes) in Table 10.5.

> Spinal signs and symptoms such as

pain, abnormal posture, or blockedmovement are an expression of theintra- or paraspinal location of thelesion (tumor? herniated disk?)

> Paravertebral sensory deficits are

observed when the root lesion islocated proximal to the exit of thedorsal ramus (i.e., at the interverte-bral foramen or proximal to it, as indisk herniation)

718 10 Spinal Radicular Syndromes

Table 10.2 Segmental innervation of the muscles of the upper and lower limbs (adapted

from R Bing, Kompendium der topischen Gehirn- und Rückenmarksdiagnostik, Basle:

Schwabe, 1953)

Abbreviations: add = adductor, artic = articularis, dig = digitorum, f = fasciae,

General Symptoms and Signs 719

Table 10.2 (Cont.)

720 10 Spinal Radicular Syndromes

Table 10.3 Synopsis of radicular syndromes

Seg-ment

Sensory deficit Motor deficit Reflex deficit Remarks

C3/4 Pain and

hypal-gesia in

shoul-der region

Diaphragmaticparesis or ple-gia

None able

detect-Partial matic paresis ismore ventral inC3 lesions, moredorsal in C4 le-sions

diaphrag-C5 Pain and

Diminishedbiceps reflex

Diminished orabsent bicepsreflex

prona-Diminished orabsent tricepsreflex

Triceps reflex key

to differential agnosis vs car-pal tunnel syn-drome

Diminishedtriceps reflex

Triceps reflex key

to differential agnosis vs ulnarnerve palsy

di-L3 From greater

trochanter

crossing over

the anterior

as-pect to the

me-dial aspect of

the thigh and

knee

Quadriceps resis

pa-Weakness ofquadriceps(knee-jerk)reflex

Differential nosis vs femoralnerve palsy: sen-sation intact indistribution ofsaphenous nerve

General Symptoms and Signs 721

Weakness ofquadriceps(knee-jerk) re-flex

Differential nosis vs femoralnerve palsy: in-volvement of ti-bialis anterior

at-of extensor gitorum brevis;

di-paresis of lis posteriorand of hip ab-duction

tibia-Absent tibialisposterior reflex(of diagnosticvalue onlywhen clearlyelicitable onopposite, unaf-fected side)

Differential nosis vs pero-neal nerve palsy:

diag-in the latter, alis posterior andhip abductionare preserved

Absent trocnemius re-flex (ankle-jerk

gas-or Achilles flex)

Diminishedquadriceps re-flex, absent ti-bialis posteriorreflex

Differential nosis vs pero-neal nerve palsy:peronei spared.Note status ofreflexes

Absent tibialisposterior andgastrocnemiusreflexes

Differential nosis vs pero-neal nerve palsy:tibialis anteriorspared Note sta-tus of reflexes

diag-722 10 Spinal Radicular Syndromes

Table 10.4 The most important normal intrinsic muscle reflexes (proprioceptive reflexes)

Masseteric reflex

(jaw jerk reflex) Tapping on chin or an instru-ment laid on the lower row of

teeth, with patient’s mouthslightly open

Brief contraction ofmasseter, partiallyclosing mouth

Masseter Trigeminal nerve CN V

Trapezius reflex Tapping on lateral portion of

tra-pezius at coracoid process Shoulder elevation Trapezius Accessory nerve CN XI, C3, C4

Scapulohumeral

reflex Tapping on medial edge of lowerhalf of scapula Adduction andexternal rotation

of the dependentarm

Infraspinatus, teresmajor Suprascapular andaxillary nerves C4, C5, C6

Biceps reflex Tapping on biceps tendon with

patient’s elbow flexed Elbow flexion Biceps brachii Musculocutaneousnerve C5, C6

Elbow flexion Biceps brachii Radial and

musculo-cutaneous nerve C5, C6

Pectoralis reflex Tapping on scapulohumeral joint

(from anterior aspect) Ventral duction ofshoulder Pectoralis major,pectoralis minor Medial and lateralpectoral nerves C5–T4

Triceps reflex Tapping on triceps tendon with

patient’s elbow flexed Elbow extension Triceps brachii Radial nerve C6, C7

Table 10.4 (Cont.)

Thumb reflex Tapping on flexor pollicis longus

tendon in distal third of forearm Flexion of interpha-langeal joint of

thumb

Flexor pollicis longus Median nerve C6, C7, C8

Wrist reflex Tapping on dorsal aspect of

wrist, proximal to radiocarpaljoint

Hand and finger tension (not alwaysseen)

ex-Hand and (long) ger extensors Radial nerve C6, C7, C8

fin-Finger flexor

re-flex Tapping on the examiner’s fin-ger, laid on the volar surface of

the patient’s hand; or tappingdirectly on the flexor tendons onthe volar surface of the hand

Flexion of the mal and middle pha-langes of the fingers(and of the wrist)

proxi-Flexor digitorumsuperficialis (andwrist flexors)

Median (and ulnar)nerves C7, C8

Trömner reflex Patient’s hand held by the

mid-dle finger; tapping on the volarsurface of the distal phalanx ofthe middle finger

Flexion of distal langes (incl thumb) Flexor digitorumprofundus Median (ulnar) nerve C7, C8, (T1)

pha-Adductor reflex Tapping medial condyle of femur Thigh adduction Adductors Obturator nerve L2, L3, L4

be-Knee extension Quadriceps femoris Femoral nerve (L2), L3, L4

Dorsiflexion andpronation of foot Long dorsiflexors offoot and toes, per-

Palpable musclecontraction

Semimembranosusand semitendinosus

reflex (triceps

su-rae reflex,

ankle-jerk reflex,

Achilles reflex)

Tapping on Achilles tendon(knee in mild flexion, ankle atright angle)

Plantar flexion offoot Gastrocnemius, so-leus, and other plan-

tar flexors

Tibial nerve S1, S2

Toe flexor reflex

(Rossolimo sign) Tapping on pads of toes Toe flexion Flexor digitorumlongus, flexor

Table 10.5 The most important normal extrinsic muscle reflexes (exteroceptive reflexes)

Pupillary reflexes

(cf Table 9.10) light, convergence constriction constrictorpupillae m CN II and III diencephalon,midbrain

Corneal reflex light touch of cornea from the

side, e.g with a strand of cotton

or tissue paper, with the eye viated nasally

de-lid closure panied by upwardmovement of theglobe = Bell’sphenomenon)

(accom-orbicularisoculi m CN V and VII pons

the globes normallyturn upward superior rectusand inferior oblique

stimulation of the soft palate

or posterior pharyngeal wallwith a tongue depressor orswab

elevation of thepalatal veil and sym-metric contraction

of the posteriorpharyngeal wall

palatal andpharyngeal muscles CN IX and X medulla

adduction andopposition of thethumb

adductor pollicis andopponens pollicismm

ulnar andmedian nn C6–T1

Table 10.5 (Cont.)

Epigastric reflex Rapid stroking with pin from

nipple downward Pulling of epigast-rium inward Upper fibers oftransversus

abdominis

Intercostal nerves T5, T6

Abdominal reflex Rapid stroking of abdominal skin

from lateral to medial Movement of skinand navel toward

stimulated side

Abdominal muscles Intercostal nerves,

hypogastric nerve,ilioinguinal nerve

T6–T12

Cremasteric

reflex Stroking of skin at upper inneraspect of thigh (or pinching of

proximal portion of adductors)

Testes drawn ward Cremaster Genital branch ofgenitofemoral nerve L1, L2

up-Gluteal reflex Stroking skin over gluteus

maxi-mus Contraction of glu-teus maximus (not

always seen)

Gluteus medius,gluteus maximus Superior and inferiorgluteal nerves L4, L5, S1

Bulbocavernosus

reflex Light pinch of glans of penis orpinprick on dorsum of penis Bulbocavernosuscontraction

(palpa-ble at root of penis,

at anogenital band,

or by digital rectalexamination)

Bulbocavernosus Pudendal nerve S3, S4

Anal wink reflex Pinprick on perianal skin or

ano-genital band, patient in lateraldecubitus position, with hip andknee flexed

Visible anal tion External analsphincter Pudendal nerve S3, S4, S5

Intervertebral Disk Disease as a Cause of Radicular

Syndromes

Pathologic Anatomy

Each intervertebral disk is composed

of a fibrous ring (annulus fibrosus)

and the soft, cartilaginous tissue that

it encloses (nucleus pulposus), which

is softest at the center of the disk As

the individual ages, the disk gradually

dries out, changes in structure, and

becomes less elastic In response to

these changes within the disk,

reac-tive spondylosis occurs in the end

plates of the adjacent vertebral

bod-ies above and below Weakened fibers

of the annulus fibrosus may rupture,

allowing disk material to escape The

difference between disk protrusion

and disk herniation is a matter of

de-gree (and is variably defined) The

herniated disk material may consist

either of fibrous tissue, or of the

ac-tual nucleus pulposus; it may

pro-trude into the spinal canal and

be-come separated from the parent disk

as a free intraspinal fragment

(sequestrum)

If there is a significant amount of disk

tissue within the spinal canal, it may

compress the dural sac and its

con-tents – i.e (depending on the level),

the spinal cord, the cauda equina, or

individual caudal nerve roots On the

other hand, a herniation pointing

posterolaterally or laterally into the

intervertebral (neural) foramen can

compress a single nerve root, causing

pain in a dermatomal distribution

and the corresponding motor,

sen-sory, and reflex deficits Similar

defi-cits can, however, be caused by

reac-tive spondylosis as well

General Signs and Symptoms of Disk Herniation

> Acute onset of symptoms, often

though not always upon heavy ertion or abrupt movement

ex-> Intense pain, usually in the spine at

first, limiting movement

> Later, radiation of pain a shorter or

longer distance into the tome of the affected root

derma-> Exacerbation of pain by certain

movements, typically extension ofthe back, and by maneuvers thatincrease the intrathoracic pressure,such as straining, coughing, orsneezing

> Vertebral syndrome with spasm

af-fecting the corresponding segment

of the spine and causing local osis

scoli-> Pain on stretching of the affected

nerve root and the peripheral nervetrunk in which it continues (e.g.,Las `egue sign in lumbar diskherniation)

> Neurologic deficits are not always

seen in the acute phase; objectivelydetectable sensory, motor, or reflexabnormalities may be lacking

> Herniation into the spinal canal can

cause spinal cord compression ifabove the L1 level, or, at lower lev-els, compression of all or part of thecauda equina

728 10 Spinal Radicular Syndromes

Cervical Disk Herniation and

Spondylosis

Clinical Features

The more prominent manifestations

of cervical disk herniation and

spon-dylosis are cervical pain, acute

torti-collis, and radicular pain in the upper

limb (brachialgia) These signs and

symptoms may arise with or without

an acute precipitating event (cervical

trauma, intense physical activity,

whiplash injury) Their onset may be

either acute or, more commonly,

sub-acute, increasing in severity over the

course of one or two days Spasm of

the neck muscles produces a rigid,

perhaps twisted neck posture

(torti-collis) A disk herniation, depending

on its location, can compress a

cervi-cal nerve root, leading to brachialgia

and radicular deficits.

The more common spondylogenic root

compression syndromes are:

> C6 syndrome: the pain radiates into

the entire arm, being most intense

on the lateral aspect of the arm and

radial aspect of the forearm down

to the thumb Hypalgesia may be

present in the same distribution,

especially distally The biceps and

brachioradialis muscles are weak,

but not atrophic The biceps reflex

is usually markedly diminished or

absent Electromyography reveals

denervation of the infraspinatus,

brachioradialis, and pronator teres

muscles, and occasionally also of

the C7 muscles (see below)

> C7 syndrome: the pain radiates

down the upper limb into the

sec-ond, third, and fourth fingers

There is hypalgesia on both the

vo-lar and the dorsal surfaces of these

fingers and in a band across the

hand, which, on the dorsal surface,

may continue proximally up the

forearm Marked triceps weakness

is usually found, not uncommonlyaccompanied by weakness of themidportion of the pectoralis majorand of the long finger flexors andpronator teres The triceps reflex isdiminished or absent

> C8 syndrome: pain and

paresthe-siae are felt in the ring and littlefingers, in which hypesthesia canalso be demonstrated The lattermay extend in a band up the ulnarsurface of the forearm The sensorydeficit is not sharply bounded bythe midline of the ring finger (as it

is in ulnar nerve palsy) Weaknessand atrophy are found in individualinterossei and in the muscles of thehypothenar eminence, but lessprominently than in ulnar nervepalsy Electromyography revealsdenervation of these muscles and

of the extensor indicis proprius.The characteristics of the individualradicular syndromes are listed in Ta-

ble 10.3 Stretching the extended arm

backward at the shoulder may

precipi-tate pain radiating into the arm, asmay axial pressure on the head when

it is slightly tilted to the affected side

(cervical compression test) Spinal cord compression is rare and, when it oc-

curs, usually chronically progressive,

in the setting of cervical spondyloticmyelopathy (see p 410) In excep-tional cases, however, it may arisesubacutely or acutely, sometimes

causing the anterior spinal artery drome (p 420) Acute or subacute spi-

syn-nal cord compression is a cal emergency

neurosurgi-Diagnostic Evaluation

The diagnosis, once made on clinicalgrounds, is confirmed by imaging

studies, principally MRI, sometimes

Intervertebral Disk Disease as a Cause of Radicular Syndromes 729

also CT or myelographic CT A

com-plete series of plain films of the

cervi-cal spine, including oblique

(forami-nal) views, demonstrates the extent

of spondyloarthrotic, uncovertebral,

and facet joint changes

Differential Diagnosis

A combination of spinal and radicular

findings should always provoke

sus-picion of a spinal tumor (particularly

metastatic) Among the rarer tumors

of the spinal nerve roots, a “dumbbell”

(or “hourglass”) neurofibroma can

cause radicular pain and neurologic

deficits as well as widening of the

in-tervertebral foramen, easily visible on

plain radiography and CT (cf

Fig 10.3) These and other tumors

af-fecting the nerve roots, as well as

lower brachial plexus lesions, cause

ra-dicular brachialgia without neck pain

Another cause of acute brachialgia is

neuralgic shoulder amyotrophy (p.

765) Finally, the pain of carpal tunnel

syndrome can sometimes ascend as

high as the neck, particularly at night

Treatment

Conservative treatment with a

cer-vical collar, local heat application,

(possibly) local anesthetic

proce-dures, and anti-inflammatory,

an-algesic, and muscle relaxant

medi-cation usually suffices

Chiropractic manipulation is

contra-indicated, as it may lead to massive

intervertebral disk herniation, or to

compression of a vertebral artery in

predisposed patients, with

result-ing damage to the spinal cord

Neurosurgical treatment: acute

spi-nal cord compression due to

cervi-cal disk herniation is a

neurosurgi-cal emergency Herniated cervineurosurgi-cal

disks may also require operation if

they cause intractable and able pain, or a persistent or pro-

unbear-gressive neurologic deficit Cervical diskectomy is usually performed through an anterior approach The

intervertebral space is emptied ofdisk material, and any compressivedisk fragments are removed In

many cases, a fusion (spondylodesis)

of the vertebral bodies above andbelow is performed, with any ofseveral available methods (autolo-gous iliac crest bone graft, cadavericbone, or metal prosthesis) Mobilecervical disk prostheses have re-cently been introduced as an alter-

native to fusion A posterior

(hemi-laminotomy) approach is times appropriate for the removal

some-of posterolateral disk fragments

Thoracic Radicular Syndromes

These syndromes are rare, and, whenthey occur, seldom spondylogenic.They are more often due to herpeszoster (shingles, p 739), referred painfrom the viscera to the correspondingzone(s) of Head, or an intraspinal tu-mor

Lumbar Disk Herniation

Anatomy

The lumbar intervertebral disks aremuch more susceptible to symptom-atic herniation than either the cervi-cal or the thoracic disks Lumbar diskherniation usually presents with ra-dicular sciatica Most lumbar diskherniations are centrolateral andtherefore compress the nerve root

that exits one level lower (Fig 10.1).

Thus, an L4–5 disk herniation usuallycompresses the L5 root (which exitsthe spinal canal between L5 and the

730 10 Spinal Radicular Syndromes